A new range of Alcatel
PABXs will cover the market from 50 to 8000 users. This range is called DHS3x.
This range is covered by several system configurations called DHS 30, 32 and 34
depending on the capacity of the system.

The whole DHS 3x program
is split in two parts: one called release 0 which includes the DHS 30/32
configuration the other called release 1 which includes the DHS 34
configuration .This document describes the architecture and the services of the
DHS 30 / 32 systems which will cover the range between 50 and 800 users.

Sometimes in this document
we use the name DHS3 which is the generic name for DHS 30 and DHS 32.

ACSE The Application
Control Service Element is an ASE that provides basic facilities for the
control of an application-association between two applications entities that
communicate by means of a presentation-connection.

API Application
Programming Interface. Set of primitives allowing an external application to
access the basic mechanisms of DHS3.

ASEApplication Service Element is a coherent set
of services used for communication at the application layer level.

ASN.1 The Abstract Syntax
Notation one is a language for specifying protocol message formats.

CCR The Commitment of
Concurrence and Recovery is an ASE that supports atomic actions by providing
concurrence controls for commitment systems and recovery procedures.

CMIP Common Management
Information Protocol specifies a protocol which is used by application layer
entities to exchange management informations.

CMISECommon Management Information Service Element
is an ASE which may be used by an application process in a management
environment to exchange information and commands for the purpose of system
management.

CSTA Computer Supported
Telecommunications Applications is a standard which enhances the capabilities
of both computing and switching networks.

CLNP ConnectionLess
Network Protocol.

CLNS ConnectionLess
Network Service.

CONS Connection Oriented
Network Service.

CSMA/CD Carrier Sense
Multiple Access with Collision Detect.

DCE Data Circuit
terminating Equipment comprises such equipment as a modem. In an X25 context
the network access and packet switching modem is classed as DCE.

DTE Data Terminal
Equipment comprises user devices such as terminals and computers. The DTE
connects to the DCE which interfaces to the network and handles the
transmission and reception fo data.

DISA Direct In System
Access; feature which allows a public subscriber to access

FTAM File Transfer, Access
and Management is an ASE which may be used by an application process for file
transfer.

FTP File Transfer
Protocol.FTP uses TCP services to control the exchange of files between two
hosts. FTP consists of both a server portion and a client portion. ASCII and binary
file transfers are supported. FTP also supports third party transfers where a
user establishes a FTP session on a local host to transfer a file between two
remote hosts.

I430/I431 Identical to
S0/S2.

I441/I451 Identical to
Q921/Q931.

IP Internet Protocol. The
Internet Protocol is designed for use in interconnected systems of
packet-switched computer communication networks.The internet protocol provides
for transmitting blocks of data called datagrams from sources to destinations,
where sources and destinations are hosts identified by fixed length addresses.
The internet protocol also provides for fragmentation and reassembly of long
datagrams, if necessary, for transmission through "small packet"
networks.

IPNS ISDN PBX Networking
Specification is an ISDN based protocol allowing telephonic features in network
configuration.

ISDN Integrated Services
Data Network.

Kermit Protocol which
offers a remote terminal service and a file transfer facility. It is packet
oriented and uses 8 data bits per byte and supports sliding windows and data
compression.

KD This is the ETSI
terminology for the digital accesses to the public switched network. KD1
represents the basic access , KD2 the primary rate access and KD3 the non ISDN
digital access ( e. g. PCM 30) LAN Local Area Network. Any physical network
technology that operates at high speed over short distances.

LAPB Link Access Procedure
Balanced. Protocol of the X25 layer 2, based on

HDLC frame exchange.

LAPD Link Access Protocol
on D channel. See Q921.

LAT Local Area Transport.
LAT means DIGITAL's communications model for resource sharing between computer
hosts connected to an Ethernet network and interactive and application
terminals and printers connected to the same network.

MAP Manufacturing
Automation Protocol. Developed by General Motors, MAP architecture is based on
OSI model. MAP products use the token bus.

MAU Medium Access Unit.

MD This is the ETSI
terminology for the private links between the PABXs ( e.g. a leased line) . MD1
represents a private 2B+D link , MD2 represents a 30B+D private link and MD3 a
proprietary digital private link.

MIB Management Information
Base is the conceptual repository of management information within an open
system.

NUMERIS Name of the French
public ISDN.

PAD Packet Assembler/
Desassembler (X3 CCITT Recommandation). Term used with packet networks that
refers to a terminal multiplexor device that forms a connection between
terminals and hosts. A PAD accepts characters from conventional terminal and
sends them across a packet network. It accepts packets from a packet network,
extracts characters, and displays them on a terminal.

PAV "Point
d'Accès Videotex". Identical to a PAD with extensions for videotex
terminals.

TCP Transmission Control
Protocol. TCP is a connection-oriented, end-to-end reliable protocol designed
to fit into a layered hierarchy of protocols which support multi-network
applications. The TCP provides for reliable inter-process communication between
pairs of processes in host computers attached to distinct but interconnected
computer communication networks.

Telnet Terminal Network.
Telnet builds on TCP services a fairly general bi-directional, eight-bit byte
oriented communications facility. Its primary goal is to allow a user at one
site to interact with a remote system at another as if the user's terminal
connected directly to the remote machine.

TOP Technical and Office
Protocol. Developed by Boeing, TOP architecture is based on OSI Reference
model. TOP products use the CSMA/CD or Token Ring access methods.

TRANSFIX Name of a French
data transmission service. It provides digital, permanent and synchronous
specialized links.

TRANSPAC Name of the
French public packet switched data network.

UDP User Datagram
Protocol. This protocol provides a procedure for application programs to send
messages to other programs with a minimum of protocol mechanism. The protocol
is transaction oriented, and delivery and duplicate protection are not
guaranteed.

V21/V22/V23 Set of CCITT
recommendations specifying asynchronous and synchronous

V24/V35 interchange
circuit definitions.

V25/V25BIS PSN automatic
answering and calling equipment.

V110 Specifies the rate
adaptation for the support of synchronous and asynchronous equipment using the
V series type interface on a PSN.

V120 Specifies the rate
adaptation for the support of synchronous and asynchronous equipment using the
V series type interface on a PSN.

VLF variable length frame

WAN Wide Area Network. A
network typically over relatively large geographic areas.

X-Windows Protocol which
defines a high level interface to drive graphic terminals.

2.2. DHS3 acronyms and abbreviations

DHS3 generic name of DHS
30 and 32. It is also the name of the project which is in charge of developing
the system

DHS3x generic name of the
new range of Alcatel PABXs. It includes the DHS 30, 32 and 34 configurations

CLUSTER set of several
interconnected crystals

CRYSTAL name of the full
meshed aarchitecture

Chapter 3 Main requirements for DHS 30-32

Chapter 4 Description of the characteristics of the
product

Chapter 5 Architecture of the system: the choices

Chapter 6 Architecture of the system: thesystem in release 0

Chapter 7 Architecture of the system: the hardware

7.3.
CPU

Two boards are needed to
implement the hardware. The CPU1 supports the processing unit while the IO1
supports the IO controller, the system clocks and power.

A connecting PCB (ATB) is
plugged in front of the CPU1 and IO1 boards and conveys the power supply for
the plateform, the AT bus, power station alarm and controller's watchdog signals.

Behind the back panel, a
connecting board (Ccard) is plugged into the DIN sockets of IO1 and CPU1. It
supports sockets for tape recorder, alarm relay logic, trunk line diversion
logic, protection key, floppy disk and RS232C links (the 4 connected to the
CPU).